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Friday April 12Friday April 1211 pm here11 pm here

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EEE 105

http://www.life.uiuc.edu/animalbiology/105/Name: eee105Password: prAIRie

SoilSoilSoilSoil

Ch. 14

SoilSoilSoilSoil

Ch. 14

Portion of the world not covered by water.

Land

Mixture of minerals, organic material, living organisms, air, and water

Soil

Soil FormationSoilSoilSoilSoil

Parent MaterialAncient rock layers with recent deposits from lava or glacial flows

Weathering

Fragmentation or chemical change of the parent material

Soil FormationSoilSoilSoilSoil

WeatheringMechanical

temperature changes & abrasion

Soil FormationSoilSoilSoilSoil

WeatheringMechanical

temperature changes & abrasion

Chemical

SoilSoilSoilSoilGlaciation

Wisconsin glaciation 18,000 years ago

SoilSoilSoilSoilGlaciation

soil deposition

SoilSoilSoilSoilGlaciation

soil deposition

moraines

SoilSoilSoilSoilGlaciation

soil deposition

moraines

Moraines formed of tillMoraines formed of till

SoilSoilSoilSoilGlaciation

soil deposition

morainesloess = wind blown dust

Soil FormationSoilSoilSoilSoil

WeatheringMechanical ChemicalBiologicalhumus = dead organic material

root hairs exchange nutrientsaerates , hydrates soil

Soil FormationSoilSoilSoilSoil

WeatheringMechanical ChemicalBiologicalhumus = dead organic material

root hairs exchange nutrientsaerates , hydrates soil

composting

Soil FormationSoilSoilSoilSoil

WeatheringMechanical ChemicalBiologicalhumus soil flora & fauna

earthworms

= dead organic material

Soil FormationSoilSoilSoilSoil

earthwormsCharles Darwin’s last book

The Formation of Vegetable Mould by the Action of Earthworms

Soil PropertiesSoil Properties• TextureTexture - Determined by the size of soil

particles.

– Too many large particles leads to extreme leaching.

– Too many small particles leads to poor drainage.

SoilSoilSoilSoil

SoilSoilSoilSoilSoil PropertiesSoil Properties

• TextureTexture

silt

clay

sand

Soil types characterized bySoil types characterized by% sand, silt, & clay% sand, silt, & clay

gravel 2 - 64 mm0.05 - 2mm

0.002 - 0.05 mm

< 0.002 mm

loess

• Soil Profile - A series of horizontal layers of different chemical composition, particle size, and amount of organic matter.

• Horizon - Each recognizable layer of the profile.

SoilSoilSoilSoil

• A Horizon - (Topsoil) Uppermost layer - contains most of the soil nutrients and organic matter.

• B Horizon - (Subsoil) Underneath topsoil. Contains less organic matter and fewer organisms, but accumulates nutrients leached from topsoil.

• C Horizon - Weathered parent material - very little organic material.

• A Horizon - (Topsoil) Uppermost layer - contains most of the soil nutrients and organic matter.

• B Horizon - (Subsoil) Underneath topsoil. Contains less organic matter and fewer organisms, but accumulates nutrients leached from topsoil.

• C Horizon - Weathered parent material - very little organic material.

SoilSoilSoilSoil

Grassland Soils

topsoil leaching

most root growth

A Horizon

low rainfall limits

A horizon supports

Usually a deep

Forest Soils

Topsoil thin

topsoil leachateforms a subsoil that supports

substantial root growth

• Mixtures ?– Over 15,000 separate soil types have

been classified in North America.

SoilSoilSoilSoil

Morrow PlotsMorrow Plots

SoilSoilSoilSoil

• Erosion - Wearing away and transportation of soil by wind and water.

SoilSoilSoilSoil

Worldwide removes 25.4 Billion tons/yr

Made worse by deforestation

Poor agricultural practices increase erosionand lead to the transport of associatedfertilizers and pesticides

and desertification

DesertificationDesertificationDesertificationDesertification

DesertificationDesertificationDesertificationDesertification

SoilSoilSoilSoil

Tombouctou, MaliTombouctou, Mali

19761976 19851985

DesertificationDesertificationDesertificationDesertification

DesertificationDesertificationDesertificationDesertification

• Climate change

• Deforestation

• Overgrazing

DesertificationDesertificationDesertificationDesertification

• The U.S.Inter-Mountain West

DesertificationDesertificationDesertificationDesertification

• The U.S.Inter-Mountain West

SalinizationSalinizationSalinizationSalinization

Calciu

mC

alcium

Sod

ium

Sod

ium

HH22OO

SalinizationSalinizationSalinizationSalinization

• Erosion - Wearing away and transportation of soil by wind and water.

SoilSoilSoilSoil

Worldwide removes 25.4 Billion tons/yr

Made worse by deforestation and desertification

Poor agricultural practices increase erosionand lead to the transport of associatedfertilizers and pesticides

• Erosion

SoilSoilSoilSoil

Most current agricultural areas lose topsoil faster than it can be replenished

Wind erosion

Water erosion

• Erosion - Wearing away and transportation of soil by wind and water.

SoilSoilSoilSoil

• Erosion

SoilSoilSoilSoil

• Erosion

SoilSoilSoilSoil

Sustainable farmingIllinois Erosion & Sediment Control Law

called “T by 2000”

T = tolerable soil loss

3-5 tons/acre/year

• Erosion

SoilSoilSoilSoil

Conservation tillage

Sustainable farming

• Erosion

SoilSoilSoilSoil

Conservation tillage

Sustainable farming

Hedgerows

• Erosion

SoilSoilSoilSoil

Conservation tillage

Sustainable farming

Hedgerows

Perimeter wetlands

• Erosion

SoilSoilSoilSoil

Great Plains have had four serious bouts of wind erosion since late 1800’s.